Graham Else from Barts BioResource in London developed a C# application for appointment booking using Twilio Voice APIs, but wanted to add appointment reminders without adding extra references to his existing project. He used AWS Lambda to automate this process by creating a lightweight solution that calls an API endpoint in his app to generate reminders. To set up the project, Graham created an IAM user and installed the AWS SDK in Visual Studio, then coded the Lambda function to call the API endpoint, which returns a response indicating whether the reminder was successful or not. He added an API controller to his existing project to handle the request from the Lambda function, and tested the Lambda function using VS Mock Lambda Test and then published it to AWS Lambda. Graham also created a CloudWatch rule to schedule the Lambda function to run daily at 3:00 PM, and demonstrated how to test and enable/disabling the rule.